(a) Field of the Invention
The present invention relates to a method and an apparatus for controlling a hybrid electric vehicle, and more particularly, to a method and an apparatus for controlling a hybrid electric vehicle that optimize driving energy of the hybrid electric vehicle in an entire route.
(b) Description of the Related Art
As is generally known in the art, a hybrid electric vehicle uses an internal combustion engine and a battery power source together. In other words, the hybrid electric vehicle efficiently combines and uses torque of the internal combustion engine and torque of a motor. In general, the hybrid electric vehicle includes an engine, a motor, an engine clutch that selectively connects the engine and the motor, a transmission, a differential gear device, a battery, a hybrid starter & generator (HSG) configured to start the engine or generate power based on an output of the engine, and wheels. The HSG may refer to an integrated starter & generator (ISG).
Further, the hybrid electric vehicle provides driving in an electric vehicle (EV) mode in which torque of the motor is used; a hybrid electric vehicle (HEV) mode in which toque of the engine is used as main torque and torque of the motor is used as auxiliary torque, by engaging or releasing the engine clutch based on acceleration intention and deceleration intention, a vehicle speed, a state of charge (SOC) of the battery, and the like; and a regenerative braking mode in which braking and inertial energy are recovered through electrical power generation of the motor while braking the vehicle or during deceleration of the vehicle by inertia to be charged in the battery. Since the hybrid electric vehicle uses both mechanical energy of the engine and electrical energy of the battery, uses optimal operation sections of the engine and the motor, and recovers the energy upon braking, fuel efficiency may be improved and the energy may be efficiently used.
According to a method for controlling a hybrid electric vehicle of the related art, to satisfy a demand torque of a driver, a torque of an engine and a torque of a motor are determined to operate the engine at an optimal operating point, thereby enabling efficient driving at a current time. However, since the conventional method does not completely reflect a change of the driving energy due to a change of a road gradient or a change in vehicle speed, it is inefficient in consideration of an entire driving route. For example, when entering an uphill or a low speed section, when a state of charge (SOC) of a battery is low, an available torque of the motor is insufficient, and excessive control is performed to satisfy the demand torque of the driver. As a result, drivability may be deteriorated. In addition, when entering a downhill or a high speed section, when the SOC of the battery is high, a charging available SOC is insufficient, and thus, regenerative braking energy may be wasted.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.